What is Fluorescein Angiography?
Fluorescein Angiography is a diagnostic procedure which uses a special camera to take a series of photographs of the retina, the light sensitive tissue in the back of the eye.
A special water-soluble dye (fluorescein) is injected into a vein in the arm. The dye travels through the veins and into the arteries which circulate throughout the body. This procedure is often confused with an X-ray angiogram where an iodine is injected into a vessel. There is no cross reaction between the fluorescein dye and the iodine dye used in other angiogram tests. If you have had a re-action to iodine dye, it does not mean you will have a reaction to the fluorescein dye. If you have ever had a fluorescein angiogram and suffered side effects from the dye, please let us know.
As the dye passes through the blood vessels of the retina, a special camera flashes a blue light into the eye and takes multiple photographs of the retina.
If the blood vessels are abnormal, the dye may leak into the retina or stain the blood vessels. Damage to the lining underneath the retina or the appearance of abnormal new blood vessels growing beneath the retina may also be revealed. The precise location of these abnormalities can be determined by a careful interpretation of the fluorescein angiogram by your ophthalmologist.
Why is Fluorescein Angiography done?
If after examining your eyes your ophthalmologist suspects abnormalities in the back of the eye, he or she may recommend fluorescein angiography. It is often done to follow the course of disease and monitor treatment results.
Diabetes, the leading cause of blindness in patients under the age of 55, can cause the blood vessels of the retina to leak fluid or blood. In some cases, these abnormalities can be treated with a laser to help prevent loss of vision.
Without the help of fluorescein angiography, your ophthalmologist would not be able to thoroughly diagnose these and other abnormalities. Knowing exactly where a leak is, for example, can guide laser treatment with pinpoint accuracy.
What are the risks of Fluorescein Angiography?
After the fluorescein dye is injected, your skin may turn yellowish for several hours. This colour disappears as the dye is filtered out of the body by the kidneys. Because the dye is removed by the kidneys, your urine will turn dark orange for up to 24 hours following the test.
Some individuals may experience slight nausea during the procedure, but this usually passes within a few seconds. If the dye leaks out of a fragile vein during the injection, some localized burning and yellow staining of the skin occurs. This burning usually lasts only a few minutes and the staining will go away in a few days.
Allergic reactions to fluorescein dye are rare. If they occur, they may cause a skin rash and itching. This is usually treated with oral or injectable antihistamines, depending on the severity of the symptoms. Even more rarely, severe allergic reactions (anaphylaxis) can occur and be life threatening. The chance of life threatening reactions occurring is 1 in 250,000. Should you experience a reaction after your angiogram, call your doctor or proceed to the nearest health care centre.
Because the most common side effect is nausea / vomiting, you are required to fast two (2) hours prior to this test.
If you are a diabetic, please eat a full meal 2 hours prior to the test and take your regular dose of insulin or diabetic medication. Please do not skip a meal. During the 2 hours prior to the test you can drink clear fluids (water) but please do not eat solid food.
Please report to the Admissions Department, located on the main floor of the hospital, for registration. The whole test from the time you come to the Admissions Department unitl you leave is approximately 2 to 3 hours.